1 files changed, 14 insertions, 0 deletions
diff --git a/builtins.c b/builtins.c
index 5751502..95b6438 100644
--- a/builtins.c
+++ b/builtins.c
@@ -32,6 +32,7 @@ BuiltinProto(builtincompare);
 BuiltinProto(builtinfunctor);
 BuiltinProto(builtinarg);
 BuiltinProto(builtinuniv);
+BuiltinProto(builtincopyterm);
 BuiltinProto(builtinis);
 BuiltinProto(builtincatch);
 BuiltinProto(builtinthrow);
@@ -98,6 +99,8 @@ findbuiltin(Term *goal)
 		return builtinarg;
 	if(Match(L"=..", 2))
 		return builtinuniv;
+	if(Match(L"copy_term", 2))
+		return builtincopyterm;
 	if(Match(L"is", 2))
 		return builtinis;
 	if(Match(L"catch", 3))
@@ -461,6 +464,17 @@ builtinuniv(Term *goal, Binding **bindings, Module *module)
 	}
 }
 
+int
+builtincopyterm(Term *goal, Binding **bindings, Module *module)
+{
+	USED(module);
+	Term *term1 = goal->children;
+	Term *term2 = term1->next;
+	Term *t = copyterm(term1, &clausenr);
+	clausenr++;
+	return unify(term2, t, bindings);
+}
+
 #define ToFloat(t) (t->tag == IntegerTerm ? (double)t->ival : t->dval)
 
 Term *